Many flights out of Edinburgh, Glasgow and other airports across Scotland have been cancelled due to ash cloud cover from the Grimsvötn volcano in Iceland.
In its latest update at 9.15am, National Air Traffic Services (NATS) said that the volcanic ash event is expected to impact airspace in Scotland and Northern England until this evening:
"Latest information from the Met Office shows that following the recent eruption of Grímsvötn in Iceland, an area of volcanic ash is forecast to affect some parts of the UK between 1300 and 1900 UK time on Tuesday 24 May."
NATS said services may be affected from the following airports at Edinburgh, Glasgow, Prestwick, Newcastle, Carlisle, Durham, Tees Valley, Cumbernauld, and Londonderry.
Passengers are being reminded to check with their airline first regarding the status of their flight before travelling to the airport.
The ash cloud was expected to cross scottish airspace today and airlines and airports put out travel warnings last night.
British Airways announced at 9.30pm: "Following forecasts of significant volcanic ash in Scottish airspace, British Airways has decided as a precaution that it will not operate any flights between London and Scotland on Tuesday May 24 that arrive in Scotland before 2pm or depart from Scotland before 2pm."
Easyjet announced at 8am today that all Edinburgh flights had been cancelled until 1pm.
The Easyjet statement said: "The CAA and the Met Office’s Volcanic Ash Advisory Centre are predicting that it is likely that there will be a high density ash cloud over Scotland from this morning. As a result of this the Civil Aviation Authority has declared a temporary danger area over Scotland from 01:00 to 13:00 hours.
In light of this information, easyJet has cancelled flights to/from Edinburgh, Glasgow, Inverness & Aberdeen, operating between 05:00hrs and 13:00hrs."
No-frills airline Ryanair also ground planes, reluctantly.
"Ryanair have been advised by the Irish Aviation Authority (IAA) that we may not operate flights to/from Glasgow Prestwick, Edinburgh or Aberdeen until at least 13:00 hrs Tuesday 24th May 2011," it said in a statement.
The statement added: "Ryanair strongly object to this decision and believe that there is no basis for these flight cancellations and will be meeting with the IAA on Tuesday morning to have this restriction on Ryanair flights removed as a matter of urgency.
Ryanair believe that there is no safety risk to aircraft on fights operating to and from Scotland and together with other airlines will be complaining to the Transport Minister and Regulatory Authorities about these latest and unnecessary cancellations."
NATS is due to make another ash update at 3pm.